Create shared instance of observer

Question

afern247 OP

Created Jun ’20

Replies 1

Boosts 0

Participants 2

I'm trying to follow the guide to setup apple pay in-app purchases and it says here:

Consider creating your observer as a shared instance of the class for global reference in any other class.

If I have:

Code Block class StoreObserver: NSObject, SKPaymentTransactionObserver {
								....
		//Initialize the store observer.
		override init() {
				super.init()
				//Other initialization here.
		}
		//Observe transaction updates.
		func paymentQueue(_ queue: SKPaymentQueue,updatedTransactions transactions: [SKPaymentTransaction]) {
				//Handle transaction states here.
		}
								....
}

and I call it with: let iapObserver = StoreObserver()

how do I create such shared instance?

Answered by Developer Tools Engineer in 616679022

This bit of the documentation is suggesting that you consider making StoreObserver a singleton—an object that (at least in non-test code) only has one instance—so that all of your store observation is handled by a single instance that’s aware of all the other observation done elsewhere in your app. To do this, you would write the class like this:

Code Block swiftclass StoreObserver: NSObject, SKPaymentTransactionObserver {
		static let shared = StoreObserver()
								....
		// ...as before...

And then always use StoreObserver.shared, not the initializer, when you need a StoreObserver.

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Answer 1

Developer Tools Engineer OP

Apple

Jun ’20

Accepted Answer

This bit of the documentation is suggesting that you consider making StoreObserver a singleton—an object that (at least in non-test code) only has one instance—so that all of your store observation is handled by a single instance that’s aware of all the other observation done elsewhere in your app. To do this, you would write the class like this:

Code Block swiftclass StoreObserver: NSObject, SKPaymentTransactionObserver {
		static let shared = StoreObserver()
								....
		// ...as before...

And then always use StoreObserver.shared, not the initializer, when you need a StoreObserver.

0